Such a matrix switch is widely known and is used in, for example, telephony, computer control applications, transmission systems etc. Using a matrix switch it is possible to connect any one input line(s) to any one output line(s). The input lines are thought of as forming the rows of the matrix, with the output lines forming the columns. The switches are located at the intersections of the rows and columns.
When such a matrix switch is used for telephony systems the input lines may be connected to the subscriber's lines and the output lines to the outgoing lines. It will be a requirement in such future telephone exchanges to terminate the subscriber's lines during open loop, tone and tone interval periods with the characteristic impedance of the line because of echo-return and cross-talk requirements. In order to satisfy these requirements it is proposed in U.S. Pat. No. 3,713,105 to replace the on/off crosspoint switches by change-over switches, which in a first position of a switch connect an input line to an output line and in a second position connect the input line to a terminating impedance. Such a matrix switch has the disadvantage that the commonly used matrix switch with on/off switches must be totally replaced by a matrix switch with change-over switches. A further disadvantage is that each crosspoint switch must be provided with an associated terminating impedance.